The present invention relates to touch fastener materials and their attachment to surfaces and, more particularly, to apparatus for attaching touch fastener material capable of self-bonding to a surface such as fabric and the like by the application of an electrical current therethrough wherein such apparatus comprises apparatus for attaching touch fastener material having a backing material with front and rear surfaces and having one portion of a touch fastening system on the front surface thereof, a layer of thermoplastic/thermosetting adhesive bonded to the rear surface, and, an electrically conductive/resistive material incorporated into the layer of adhesive capable of producing sufficient heat in the adhesive when a low voltage and high current electrical source is applied therethrough to cause the adhesive to adhere to the surface of an article with which it is in contact, wherein the apparatus comprises support means for supporting the article with the surface thereof exposed and the touch fastener material disposed thereon; compression means for releasably bearing against the front surface of the touch fastener material to hold it and its adhesive against the surface of the article; a plurality of contact means for releasably making electrical contact with the electrically conductive/resistive material in the adhesive when the compression means is bearing against the front surface of the touch fastener material; and, electrical means for applying low electrical current to flow through the electrically conductive/resistive material in the adhesive between respective ones of the contacts to heat the adhesive to its point of melting and adhesion.
Touch fastening systems such as those sold by the assignee of the present application under the trademark VELCRO are well known in the art and are continually being adapted to new uses as their value and ease of use becomes more and more recognized and appreciated. As used herein, the term "touch fastener", and similar designations, refers to a first planar backing material having a surface carrying hooks, mushrooms, balls on stems, pigtails, or the like, capable of engaging loops, hooks, mushrooms, balls on stems, pigtails, or the like carried by a second planar backing material to releasably fasten components together. In this specification "touch fastener" shall also be construed to include zip fasteners and buttons, press studs and the like when attached to a planar backing for mounting to a component. For convenience only, hook and loop type touch fastening material is shown in the drawings.
Where porous materials and surfaces are involved, a popular method of attaching or bonding the touch fastener materials to the components is the use of heat-activated adhesives of a type well known in the art which are thermosetting and thermoplastic in nature. Often, the heat-activated adhesive can be applied by injecting it from a hot extruding "gun" between two surfaces to be joined (or deposited onto one of them) and then pressing the surfaces together while the adhesive is in its thermoplastic state.
There are many applications involving the application of touch fastener materials with adhesive, however, where the use of a so-called "glue gun" is not an approach of choice. For example, such a situation exists where lightweight fabrics are involved, as opposed to applications employing canvas, or the like, where spot fastening with a glue gun is not a problem. Were there an alternative manner of applying the touch fastener materials with the adhesive in such more delicate applications, it would be gratefully accepted and adopted. In my co-pending application titled TOUCH FASTENER WITH SELF-HEATING ATTACHMENT ADHESIVE, filed on even date herewith and assigned to the assignee of this invention, I disclosed touch fastening materials incorporating pre-applied heat-activated thermoplastic/thermosetting adhesives which are self-heating through the application of an electrical current therethrough.
Touch fastener material according to the above-referenced co-pending application in one embodiment thereof is shown in FIGS. 1-4. The material itself is shown in exploded view in FIG. 1 and generally indicated therein as 10. The material 10 comprises a strip of touch fastener material 12 with a self-heating adhesive on the back surface thereof. For purposes of description only, the touch fastener material 12 is a conventional piece of the hook portion of hook and loop type fastening material comprising a porous backing material having a plurality of engaging hooks on the front surface thereof. The adhesive comprises a first layer 14 of thermoplastic adhesive of a type generally well known in the art and commercially available from any sources. A strip of electrically conductive/resistive metal foil 16, such as aluminum foil, is disposed between the first layer 14 of adhesive and a second layer 18 of the same material. In the form as intended for commercial sale ready for attachment, the components of FIG. 1 are heat bonded together as shown in FIG. 2. The layers 14, 18 of adhesive are bonded to the foil 16 and the first layer 14 of adhesive is bonded to the back surface of the touch fastener material 12.
To attach the touch fastener of the present invention to a strip of fabric 20, for example, it is positioned as shown in FIG. 3 with the second layer 18 of adhesive contacting the fabric 20. A plurality of contact pins 22 are then pushed through the touch fastener material 12 and/or the fabric 20 into contact with the foil 16. Alternative pins 22 are connected to positive (+) and negative (-) low voltage sources having high current capability and the high current is caused to flow through the foil 16 between the pins 22 causing the foil 16 to heat due to its electrical resistance and thereby heat the layers 14, 18 of adhesive to their thermoplastic/thermosetting level. Second layer 18 thereupon bonds to the surface of the fabric 20.
In a second embodiment of the material of the above-referenced co-pending application, the adhesive has electrically conductive/resistive particles mixed therein in place of the metal foil of the previously described embodiment. When the contact pins 22 are stuck into the adhesive, they make electrical contact with the particles. The particles, in turn, resistively conduct the current from one to another causing heat to be generated in the same manner as the foil.
Since the material of the abovereferenced co-pending application did not exist until my invention thereof, there is, accordingly, no device for attaching it on a commercial or high production basis in the same way that a sewing machine can be used for easily and quickly performing sewing operations that would, otherwise, have to be accomplished by hand.
Wherefore, it is the object of the present invention to provide apparatus for attaching the touch fastening materials of my co-pending application which incorporate pre-applied heat-activated thermoplastic/thermosetting adhesives which are self-heating through the application of an electrical current therethrough.